The disclosure relates generally to machining, and more particularly, to adaptive machining of turbomachine blade shroud hard faces.
In a turbomachine, blades are used to generate power from a flow of a working fluid. In particular, a number of blades may be coupled to a rotor to impart rotational motion to the rotor from a flow of a working fluid thereover. Turbomachine blades are initially shaped based on ideal manufacturing models that create highly efficient blades. Each turbomachine blade includes a number of intricate turns and mating surfaces to allow for the blades to collectively perform their function. For example, each blade may include a shroud at an outer end thereof that includes a hard face that engages with a mating hard surface of an adjacent blade's shroud. Hard faces are parts of the shroud that include wear material and come into contact during operation to dampen vibration. During turbine engine operation, shrouded turbine blades are subject to high amounts of distortion and twist. A contact gap between two adjacent blades is critical to ensure bucket engagement during turbomachine operation. As the turbomachine blades wear, the contact gap between two adjacent blades increases resulting in inadequate blade engagement. Consequently, turbomachine blade hard faces often require restoration during periodic repair processes.
During the restoration process, blades are machined in an attempt to return them to their manufacturing model that typically represents a nominal condition (sometimes referred to as ‘dovetail datum structure’). A challenge in restoring the blades to the modeled state is that the combination of the high amount distortion and twist positions the hard faces such that they are no longer where the nominal model predicts. Machining the hard faces on a blade based on the nominal part dimensions is inadequate because it may require unnecessary machining removal on one hard face of the shroud and/or unnecessary addition of material on another hard face of the shroud for highly distorted parts. The resulting inaccurate machining may impact part life.